Bipolar sphincterotome

ABSTRACT

A bipolar sphincterotome may include an elongate tubular member, a cutting wire, and a return path. The return path may include a conductive ink portion disposed on an outer surface at a distal portion of the tubular member. The return path may also include a return wire disposed within the tubular member that is electrically coupled to the conductive ink portion. In some example embodiments, the return wire may be disposed within a lumen configured to have two or more functions, one of which being to house the return wire. Additionally, in some example embodiments, the conductive ink portion may be circumferentially disposed on the outer surface to provide visual access to a wire guide lumen. Also, for some example embodiments, the bipolar sphincterotome may include two electrically isolated return paths.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of co-pending U.S.Non-Provisional application Ser. No. 14/139,214, filed Dec. 23, 2013(now U.S. Pat. No. 9,844,407), which claims the benefit of U.S.Provisional Application No. 61/746,162, filed Dec. 27, 2012. Thecontents of U.S. Non-Provisional application Ser. No. 14/139,214 (nowU.S. Pat. No. 9,844,407) and U.S. Provisional Application No. 61/746,162are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates generally to medical devices, and moreparticularly to bipolar sphincterotomes.

BACKGROUND

A sphincterotome is a medical device that is used to perform asphincterotomy, which involves cutting a sphincter muscle, such as thesphincter of Oddi. The sphincter muscle may need to be cut to relieveits constrictive nature and allow one or more medical devices throughthe muscle. For example, problems occurring in the biliary tree, such asthe formation of bile duct stones or papillary stenosis, may be treatedusing medical devices that are delivered into the biliary tree. In orderto access the biliary tree, the medical devices may pass through thesphincter of Oddi. To facilitate passage of the medical devices throughthe sphincter of Oddi, the sphincter muscle may be cut using asphincterotome.

A sphincterotome may generally include an elongate tubular member, suchas a catheter, and a cutting wire that is used to cut the sphinctermuscle. The cutting wire may extend through a lumen of the catheter,except at a distal portion of the catheter, where the cutting wire mayproject from and be exposed outside of the catheter. The exposedportion, which may be referred to as a cutting edge, may be used to cutthe sphincter muscle.

A sphincterotomy generally involves a two-part process: cannulation ofthe biliary tree and cutting the sphincter muscle by sending electriccurrent through the cutting wire (i.e, electrosurgery). Cannulation ofthe biliary tree may include inserting the distal portion of thecatheter into the papilla and using the distal portion and the cuttingedge to lift an upper portion (i.e., the roof) of the papilla. The roofof the papilla may be lifted by proximally pulling the cutting wiretaut, causing the distal portion of the tubular member to bow and forman arc. After cannulation, the electric current may be provided to thecutting edge to cut the sphincter muscle.

BRIEF SUMMARY

In a first aspect, a bipolar sphincterotome to perform a sphincterotomyat a treatment site is provided. The bipolar sphincterotome includes anelongate tubular member; a cutting wire disposed within the tubularmember; and a return path. The return path includes a conductivematerial portion disposed on an outer surface at a distal portion of thetubular member, and a return wire electrically coupled to the conductivematerial portion, where the return wire is disposed within the tubularmember. The conductive material portion may have a circumferentialdisposition on the outer surface that provides visual access to a wireguide lumen extending within the tubular member.

In a second aspect, a bipolar sphincterotome to perform a sphincterotomyat a treatment site within a patient is provided. The bipolarsphincterotome includes an elongate tubular member; a cutting wiredisposed within the tubular member, except for a cutting edge of thecutting wire, where the cutting edge protrudes from the tubular member;a first return path; and a second return path substantially electricallyisolated from the first return path. The first return path includes afirst return wire, and the second return path comprises a second returnwire. The first and second return wires longitudinally extend within thetubular member from a distal portion to a proximal portion of thetubular member.

In a third aspect, a method of adhering conductive ink to an outersurface of an elongate tubular member of a medical device, the elongatetubular member comprising polytetrafluoroethylene, is provided. Themethod includes: applying a primer ink to the outer surface of theelongate tubular member; and applying the conductive ink over the primerink.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional side view of a bipolar sphincterotome.

FIG. 1A shows cross-sectional side view of an alternative embodiment ofa distal portion of the bipolar sphincterotome shown in FIG. 1.

FIG. 2 shows a cross-sectional axial view of the distal portion of thebipolar sphincterotome of FIG. 1, showing a circumferential orientationof a conductive ink portion.

FIG. 3 shows a cross-section axial view of the distal portion of thebipolar sphincterotome of FIG. 1, showing an alternative circumferentialorientation of the conductive ink portion.

FIG. 4 shows a cross-sectional axial view of the bipolar sphincterotomeof FIG. 1 taken proximal a coupling area of a return path, showing areturn wire disposed in a lumen having multiple functions.

FIG. 5 shows a cross-sectional axial view of an alternative embodimentof the cross-section of the bipolar sphincterotome shown in FIG. 4,where the return wire is embedded in a tubular member of the bipolarsphincterotome.

FIG. 6 shows a cross-sectional axial view of another alternativeembodiment of the cross-section of the bipolar sphincterotome shown inFIG. 4, where the return wire is disposed in a lumen having a solefunction to house the return wire.

FIG. 7. shows a side view of the distal portion of the bipolarsphincterotome of FIG. 1, where the return path is a single return path.

FIG. 8. shows a side view of an alternative embodiment of the distalportion of the sphincterotome of FIG. 1, where the return path includestwo return paths and where a gap separating two conductive ink portionsextends in a substantially straight direction.

FIG. 9. shows a side view of a second alternative embodiment of thedistal portion of the sphincterotome of FIG. 1, where the return pathincludes two return paths and where the gap has a zig-zag pattern.

FIG. 10. shows a side view of a third alternative embodiment of thedistal portion of the sphincterotome of FIG. 1, where the return pathincludes two return paths and where the gap has a sinusoidal pattern.

FIG. 11. shows a cross-sectional view of cabling electrically coupling asingle return wire with a single wire in the cabling.

FIG. 12. shows a cross-sectional view of an alternative embodiment ofthe cabling of FIG. 11, where the cabling includes two wires, eachelectrically coupled to a return wire.

FIG. 13 shows a cross-sectional view of a second alternative embodimentof the cabling of FIG. 11, where the cabling includes two wires shortedtogether and electrically coupled to a single return wire.

FIG. 14 shows a cross-sectional view of a third alternative embodimentof the cabling of FIG. 11, where the cabling includes two wires, andwhere one of the wires includes a resistive element.

FIG. 15 shows a cross-sectional view of a fourth alternative embodimentof the cabling of FIG. 11, where the cabling includes two wires, andwhere each of the wires includes a resistive element.

DETAILED DESCRIPTION

The present disclosure describes various embodiments of a sphincterotomehaving a bipolar configuration, otherwise referred to as a bipolarsphincterotome. Sphincterotomes may include an elongate tubular member,such as a catheter, and a cutting wire used to cut a sphincter musclewhen performing a sphincterotomy. The cutting wire may be coupled toand/or in electrical communication with a radio frequency (RF)generator, such as an electrosurgical unit (ESU). When the RF generatoris activated, the RF generator may supply electrical current to thecutting wire, which may cut the sphincter muscle. The electrical currentmay travel along the cutting wire, through the sphincter muscle, andthen along a return path, which completes the circuit.

The return path for sphincterotomes having a monopolar configuration mayinclude a neutral electrode, which may be a solid, neutral electrode, ora split neutral electrode, and which may be positioned on the thigh ofthe patient undergoing the sphincterotomy. The return path for bipolarsphincterotomes may differ from monopolar sphincterotomes in that, likethe cutting wire (i.e., the active path), the return path may beattached to, integrated with, disposed within, or included as part ofthe catheter.

FIG. 1 shows a partially cross-sectional side view of an example bipolarsphincterotome 100. The example bipolar sphincterotome 100 may includean elongate, tubular member 102 that has a proximal portion 104extending to a distal portion 106. A cutting wire 108 used to cut thesphincter muscle may be disposed within a lumen (not shown in FIG. 1) ofthe tubular member 102 from the proximal portion 104 to the distalportion 106. At the distal portion 106, the cutting wire 108 may extendor protrude from within the tubular member 102, through a first opening110 of the tubular member 102, to outside the tubular member 102.Outside the tubular member 102, the cutting wire 108 may longitudinallyextend substantially parallel with the tubular member 102 to a secondopening or anchor point 112 of the tubular member 102 that is distal thefirst opening 110, where a distal end of the cutting wire 108 mayre-enter and/or be fixedly attached to the tubular member 102. Theexposed portion 114 of the cutting wire 108 may be referred to as acutting edge, which may be the portion of the cutting wire 108 that cutsthe sphincter muscle.

The bipolar sphincterotome 100 may further include a return path 124.For the bipolar configuration, the return path 124 may be attached to,adhered to, integrated with, disposed within, or included as part of thetubular member 102. In the example embodiment of the bipolarsphincterotome 100, the return path 124 may include conductive materialportion 126 disposed on or cover an outer surface of the distal portion106 of the tubular member 102, and a return wire 132 electricallycoupled to the conductive ink portion 126.

In one example embodiment of the return path 124, the conductivematerial portion 126 may be made of conductive ink. The conductivematerial portion 126 is hereafter referred to as a conductive inkportion 126, although conductive materials other than ink may be used.The conductive ink portion 126 may be attached to an outer surface ofthe tubular member 102 at the distal portion 106. In some exampleembodiments, the conductive ink (or alternatively referred to asconductive paint or conductive coating) making up the conductive inkportion 126 may have a thickness in a range of about 20-40 micrometers(microns), although other thicknesses may be used, including up to 500microns. Particles of the conductive ink may have a size in a range ofabout 3-30 microns. Also, the particles may be made of silver and/or maybe suspended in a polyester binder. Additionally, the conductive ink mayhave a viscosity of about 250 centipoise (cP), although otherviscosities may be used, including up to about 10,000 cP. Also, aresistance of the conductive ink portion 126 may be in a range of aboutzero (or substantially zero) to ten Ohms, when measured longitudinally.An example conductive ink, which may or may not include all of theabove-described properties, may be AG-510 Silver Filled ElectricallyConductive Screen Printable Ink/Coating by Conductive Compounds, Inc.

The conductive ink portion 126 may extend distally past the anchor point112. Extending the conductive ink portion 126 distally past the anchorpoint 112 may ensure or increase the likelihood that the return path 124contacts the sphincter muscle (or tissue near the sphincter muscle) tomake a proper connection at the treatment site. Additionally, theconductive ink portion 126 may distally extend to a position before adistal tip 128 or sufficiently away from an opening of a wire guidelumen (not shown in FIG. 1) at the distal tip 128 so that a wire guidein the wire guide lumen is not part of or is isolated from the returnpath 124. In addition, the conductive ink portion 126 may proximallyextend past the first opening 110.

The conductive ink portion 126 may be electrically coupled to a returnwire 132, which may form and/or be part of the return path 124. Thereturn wire 132 may extend within the tubular member 102 from where thereturn wire 132 is electrically coupled to the conductive ink portion126 to the proximal portion 104. The return wire 132 may extend withinthe tubular member 102 generally or substantially parallel to thecutting wire 108. In addition, the return wire 132 may extend within thetubular member 102 in various locations relative to the cutting wire108. FIG. 1 shows the active wire 108 and the return wire 132 generallyin the same cross-sectional plane. However, as shown in FIGS. 4-6, thereturn wire 132 may be disposed within the tubular member 102 in variouslocations relative to the cutting wire 108. Also, as described in moredetail below, the return wire 132 may be disposed and/or extend within alumen of the tubular member 102, or alternatively, may be embeddedwithin and/or coextruded with the tubular member 102.

The conductive ink portion 126 may be electrically coupled to the returnwire 132 in various ways. For example, as shown in FIG. 1, theconductive ink portion 126 may proximally extend to a conductive ring orcannula 130, which may electrically couple the conductive ink portion126 to the return wire 132. In some example embodiments, the conductivecannula 130 may be attached or crimped to the outer surface of thetubular member 102. The conductive cannula 130 may be made of metal,such as stainless steel, silver, gold, tantalum, or tungsten, asexamples. The conductive ink may be applied to and/or deposited overand/or under at least a portion of the conductive cannula 130 so thatthe conductive ink portion 126 and the conductive cannula 130 areelectrically coupled, and the conductive cannula 130 is part of thereturn path 124. As shown in FIG. 1, the return wire 132 may beconnected to the conductive cannula 130 to be electrically coupled withthe conductive ink portion 126. For example, the return wire 132 may becurled at its distal end to extend to the outer surface of the tubularmember 102, and the conductive cannula may be crimped to the tubularmember 102 over the distal end of the return wire 132.

In some embodiments, the bipolar sphincterotome 100 may further includea tube 134 disposed over the conductive cannula 130 and the conductiveink that is covering or disposed on the conductive cannula 130. As shownin FIG. 1, the tube 134 may distally extend to the first opening 110 inthe tubular member 102, or alternatively to a position in between thecannula 130 and the first opening 110. In some embodiments, the tube 134may be a shrink tube 134 that conforms to the surface that the shrinktube 134 is covering, such as when heat is applied to the shrink tube134. The tube 134 may have a thickness of about 0.0002 inches, althoughother thicknesses may be used. The tube 134 may be disposed over thecannula 130 to provide a relief to the strain caused by varyingflexibilities between the tubular member 102 (which may be relativelyflexible) and the metal cannula 130 (which may be relatively rigid).Additionally, the tube 134 may provide a protective coating or scratchresistance, which may prevent or minimize the conductive ink from beingscratched off.

For some example embodiments of the tube 134, an inner surface of thetube 134 may be coated with one or more conductive materials, such as aconductive ink, a conductive powder, a conductive adhesive, orcombinations thereof, as examples. The conductive material may be thesame material as or may be a different material then the conductive inkthat makes up the conductive ink portion 126. The tube 134, with aninner surface coated with a conductive material, may enhance electricalcontinuity between the conductive ink portion 126 and the conductivecannula 130.

FIG. 1 shows a part of the conductive ink portion 126 disposed ordeposited over the conductive cannula 130 so that the conductive inkportion 126 and the conductive cannula 130 may be electrically connectedwith each other. In an alternative embodiment of the distal portion 106,the conductive ink portion 126 may be deposited on the outer surface ofthe tubular member 102 and/or the conductive cannula 130 may bepositioned relative to the conductive ink portion so that they arephysically separated, and/or so that by themselves, they areelectrically disconnected from each other. For this alternativeembodiment, the tube 134 with an inner surface being coated with aconductive material may be disposed over both the conductive cannula 130and the conductive ink portion 126 to electrically connect theconductive ink portion 126 with the conductive cannula 130.

In still other alternative embodiments, the tube 134 may be replacedwith an adhesive, an epoxy, a notched cannula, a cannula with a wavy orflexible distal tip, or any combination thereof. In still otheralternative embodiments, the tube 134 or other covering or coating maynot be included.

Referring to FIG. 1A, another alternative example embodiment of thebipolar sphincterotome 100 may include an opening 150 in a wall of thetubular member 102 instead of the metal cannula 130 to electricallycouple the return wire 132 with the conductive ink portion 126. Theopening 150, such as a skive or a cut in the tubular member 102, mayextend from the outer surface of the tubular member 102 to an innerportion where a distal end of the return wire 132 is disposed. Theconductive ink portion 126 may be deposited to extend within the opening150 so that the conductive ink portion 126 is electrically coupled tothe return path 132.

Referring back to FIG. 1, the bipolar sphincterotome 100 may furtherinclude a handle assembly 116 coupled to the proximal portion 104 and/ora proximal end of the cutting wire 108. The handle assembly 116 may beoperatively coupled to the cutting wire 108 to move the cutting edge 114between a relaxed state and a cutting state. For example, the handleassembly 116 may be configured to move the cutting edge 114 from therelaxed state to the cutting state by proximally pulling the cuttingwire 108 taut. When the cutting wire 108 is pulled, the distal portion106 of the tubular member 102 may bow or curl, forming an arc. The tautcutting edge 114 may form a secant of the arc. When the distal portion106 is curled and the cutting edge 114 is taut, the distal portion 106and the cutting edge 114 may be configured or in position to cut thesphincter muscle. The handle assembly 116 may also be configured torelease or distally push the cutting wire 108 to uncurl the distalportion 106 and to move the cutting edge 114 from the taut state to therelaxed state. When the distal portion 106 is uncurled (or at least in aposition that is curled to a lesser degree than when the cutting edge114 is taut) and the cutting edge 114 is in the relaxed state, thedistal portion 106 and the cutting edge 114 may not be configured to cutthe sphincter muscle and/or may be configured or in position to be movedto and from the treatment site.

Both the cutting wire 108 and the return wire 132 may be electricallycoupled to a power source 118, such as a radio frequency (RF) generatoror an electrosurgical unit (ESU), that supplies electrical current tothe cutting wire 108 to perform the electrosurgery. In one exampleembodiment, the cutting wire 108 may be electrically coupled to thepower source 118 by proximally extending to the handle assembly 116,where the proximal end of the cutting wire 108 may be connected to ametallic pin 134 that extends to a port 136 of the handle assembly 116.The metallic pin 134 and/or the port 136 may be adaptable to connect tosupply cabling 138 that may connect to an active port 140 of the powersource 118.

The return wire 132 may be electrically coupled to the power source 118by distally extending through a side port 142 connected to the tubularmember 102, where a proximal end of the return wire 132 may be connectedto return cabling 144, such as by soldering the return wire with one ormore wires of the return cabling 144. Alternatively, the return wire 132may be connected to the return cabling 144 by crimping the returncabling to the return wire 132 disposed inside a metal cannula. Thereturn cabling 144 may be adaptable to connect to a return port 146 ofthe power source 118. When the power source 118 is activated, the powersource 118 may deliver electric current to the cutting wire 108 via thesupply cabling 138 and the metallic pin 134. The electrical current maypass through the cutting wire 108 to the cutting edge 114, whereelectrosurgery may be performed on sphincter muscle. The electricalcurrent may pass through the sphincter muscle, which acts as a load, andthen along the return path 124, including the conductive ink portion 126and the return path, back to the power source 118 via the return cabling144.

FIG. 2 shows a cross-sectional view of an example embodiment of thebipolar sphincterotome 100 taken along line 2-2 in FIG. 1. The tubularmember 102 may include a wire guide lumen 202 that is configured toreceive and have movably disposed therethrough a wire guide 203. Inoperation, the wire guide 203 may be delivered to the treatment sitewithin the patient. The wire guide lumen 202 may be inserted over thewire guide 203, and the distal portion 106 of the bipolar sphincterotome100 may be delivered to the treatment site. The tubular member 102 mayinclude one or more other lumens, such as an injection lumen 204, whichmay be used to deliver contrast to the treatment site.

As shown in FIG. 2, the conductive ink portion 126 may becircumferentially disposed partially around the outer surface of thetubular member 102. The circumferential disposition of the conductiveink portion 126 may have an orientation that is defined or determinedrelative to a radial orientation of the anchor point 112 or the cuttingedge 114 of the cutting wire 108. The radial orientation of the anchorpoint 112 or the cutting edge 114 may be defined by a direction in whichthe cutting edge 114 radially extends from the tubular member and/or maybe identified by a dotted arrow 206, which extends from a center pointor origin of the tubular member 102 through the anchor point 112. Theorientation of the circumferential disposition of the conductive inkportion 126 may be identified by a dotted line 208 extending through thecircumferential ends 210 a, 210 b of the conductive ink portion 126. Theorientation of the circumferential disposition of the conductive inkportion 126 relative to the radial orientation of the anchor point 112or cutting edge 114 may be defined or determined as a radial differenceor difference in degrees between the dotted lines 206 and 208. In oneexample configuration, as shown FIG. 2, the circumferential dispositionof the conductive ink portion 126 may be oriented perpendicular orsubstantially perpendicular to the radial orientation of the anchorpoint 112 or the cutting edge 114, as identified by the ninety-degreeradial difference or perpendicular intersection between the dotted lines206 and 208.

The tubular member 102 may be made of a clear, or at least semi-clear,material. The tubular member 102 may be clear or semi-clear forvisualization purposes. For example, a side viewing endoscope mayprovide a physician or other operator of the bipolar sphincterotome 100visual access to the side of the tubular member 102. The clear materialmay further provide the physician or operator visual access to insidethe tubular member 102, such as visual access to one or more lumens ofthe tubular member 102. In particular, the clear material may providevisual access to the wire guide lumen 202 so that the physician oroperator may see the wire guide 203 move through the wire guide lumen202.

However, the conductive ink portion 126 may be an opaque orsubstantially opaque material, which may block or impede visual accessto within the tubular member 102, and particularly the wire guide lumen202. As such, it may be desirable to orient the conductive ink portion126 around the tubular member 102 in a way that provides for visualaccess to the wire guide lumen 202. In some example tubular memberconfigurations as shown in FIG. 2, the wire guide lumen 202 may bedisposed within the tubular member 102 relative to the anchor point 112or the wire guide 108 such that a perpendicular orientation of thecircumferential disposition of the conductive ink portion 126 relativeto the radial orientation of the anchor point 112 or the cutting edge114 may block or prevent visual access to the wire guide lumen 202. FIG.2 shows how visual access, represented by eyeball 212 and dotted lines214, 216, may be blocked by the perpendicular orientation.

FIG. 3 shows a cross-sectional view of an alternative embodiment of thebipolar sphincterotome 100 taken along line 2-2 in FIG. 1. In thealternative embodiment shown in FIG. 3, the circumferential dispositionof the conductive ink portion 102 may have an orientation that is offset(denoted by dotted line 308) from the perpendicular orientation (denotedby dotted line 208) to unblock or provide visual access to the wireguide lumen 202. In some example configurations, the offset (denoted byarrow 318) may be about thirty-degrees, although any degree offset maybe utilized that provides visual access to the wire guide lumen. Also,the direction in which the offset is made may depend on the side of thebipolar sphincterotome 100 to which the side viewing endoscope isconfigured to have visual access. For example, when looking at thecross-section of the bipolar sphincterotome 100 from the perspectiveshown in FIG. 3, visual access (denoted by the eyeball 212 and thedotted lines 214, 216), may be on the “right” side. As such, the offsetmay be in a clockwise direction. Alternatively, if visual access were onthe opposite side (e.g., the “left” side from the perspective in FIG.3), then the offset may be in a counter-clockwise direction.

FIGS. 2 and 3 show that the circumferential disposition of theconductive ink portion 126 extends about halfway around the tubularmember (i.e., the dotted line 206 extends through the center or originof the tubular member 102). In alternative configurations, thecircumferential disposition of the conductive ink portion 126 may extendless than halfway or more than halfway around the tubular member.

FIG. 4 shows a cross-sectional view of an embodiment of thesphincterotome 100 taken along line 4-4 in FIG. 1. The cross-sectionalview shown in FIG. 4 may be representative of the cross-section of thetubular member 102 proximal the conductive cannula 130. FIG. 4 shows thewire guide 203 disposed within the wire guide lumen, as well as thecutting wire 108 disposed within a cutting wire lumen 402. In addition,as shown in FIG. 4, the return wire 132 may be disposed and extendwithin the injection lumen 204. As such, the injection lumen 204 mayserve a dual role or have two functions—to deliver contrast to thetreatment site, and to house the return path 132 of the bipolarsphincterotome 100. Although the embodiment in FIG. 4 shows the returnwire 132 disposed within the injection lumen 204, the return wire 132may be disposed in a different lumen than the injection lumen 204.Generally, the sphincterotome 100 may be configured so that one of aplurality of lumens within the tubular member 102 has dual or multiplepurposes or functions, one of which is to house the return wire 132.

FIG. 5 shows a cross-sectional view of an alternative embodiment of thebipolar sphincterotome 100 taken along line 4-4 in FIG. 1. In thealternative embodiment, the return wire 132 may be embedded withinand/or an integral part of the tubular member 102, rather than bedisposed within the injection lumen 204. As such, none of the lumens inthe tubular member 102 may function to house the return wire 132. Inthis alternative embodiment, the tubular member 102 and the return wire132 may be co-extruded to embed or integrate the return wire 132 withthe tubular member 102.

FIG. 6 shows a cross-sectional view of a second alternative embodimentof the bipolar sphincterotome 100 taken along line 4-4 in FIG. 1. In thesecond alternative embodiment, the tubular member 102 includes a lumen602 having a single function or purpose to house the return wire 132.

The tubular member 102 may be made of various materials or combinationsof materials including, but not limited to, fluoropolymer materials suchas polytetrafluoroethylene (PTFE) or perfluoroalkoxy (PFA),polyethylene, nylon, or fluorinated ethylene, as examples. Where thetubular member is made of a fluoropolymer material such as PTFE or PFA,to optimally adhere the conductive ink portion 126 to the fluoropolymertubular member 102, a primer ink or base ink may be adhered or appliedto the tubular member 102 before the conductive ink is applied. Theprimer ink may have characteristics or qualities that enable the primerink to be adhesive to both the fluoropolymer material and to theconductive ink. The conductive ink may then be applied over the primerink. The primer ink may enhance or increase the adhesiveness or bondbetween the fluoropolymer tubular member 102 and the conductive ink 126,which may prevent or reduce the ability for the conductive ink to berubbed off or otherwise removed from tubular member 102. Additionally,the conductive ink and/or the primer ink may be applied or deposited onthe tubular member in any of various ways, such as spraying, padprinting, rolling, brushing, dipping, or electroplating, as examples.

In some example embodiments, the return path 124 may include a singlereturn path. For these example embodiments, the conductive ink portion126 may include a single, continuous portion electrically coupled to asingle return wire 132. FIG. 7 shows a side view of an exampleembodiment of the distal portion 104 from an angle showing most if notall of the conductive ink portion 126, where the return path 124 is asingle return path.

In alternative example embodiments, the return path 124 may includemultiple, such as two, return paths. The multiple return paths may beelectrically isolated or substantially electrically isolated from eachother. Multiple return paths may be included to provide a safety featurefor the bipolar sphincterotome 100. Some power sources 118 (FIG. 1) maybe configured for dual return paths in that the power sources 118 may beconfigured to prevent output of the electrical current unless each ofthe return paths are in contact with the sphincter muscle or thesurrounding tissue. This ensures adequate placement of the distalportion at the treatment site before the electrical current may besupplied from the power source 118. Additionally, if any of the returnpaths becomes disconnected, such as through fracture or burnout, thepower source 118 may be configured to detect or recognize thedisconnection and prevent the electrical current from being supplied tothe treatment site.

FIG. 8 shows a side view of an example embodiment of the distal portion106 from an angle showing most if not all of the conductive ink portion126, where the return path includes a dual return path. The dual returnpath may include a first return path 824 a and a second return path 824b. To form the first and second paths 824 a, 824 b, the conductive inkportion 126 may include two sub-portions or strips, including a firstsub-portion 826 a and a second sub-portion 826 b. The first sub-portion826 a and the second sub-portion 826 b may be electrically isolated fromeach other. The conductive ink making up the first and secondsub-portions 826 a, 826 b may be deposited to form a gap or spacing 860in between the first and second sub-portions 826 a, 826 b toelectrically isolate the first and second sub-portions 826 a, 826 b fromeach other. In some example configurations, a width of the gap 860 maybe about 0.040 inches, although other sizes for the width may be used.

The first and second sub-portions 826 a, 826 b may each be electricallycoupled to a respective return wire. For example, the first sub-portion826 a may be electrically coupled to a first return wire 832 a and thesecond sub-portion 826 b may be electrically coupled to a second returnwire 832 b. In some example embodiments, the first and secondsub-portions 826 a, 826 b may be electrically coupled to theirrespective return wires 832 a, 832 b at opposing ends of thesub-portions 826 a, 826 b. Additionally, the first and secondsub-portions 826 a, 826 b may be electrically coupled to theirrespective return wires 832 a, 832 b in various ways, such as thosedescribed above. For example, as shown in FIG. 8, two metal cannulas 830a, 830 b may be used to electrically couple the sub-portions 826 a, 826b with their respective return wires 832 a, 832 b. The metal cannulas830 a, 830 b may be disposed at opposing ends of the conductive inkportion 126 such that only one of the sub-portions 826 a, 826 b iscoupled to each of the metal cannulas 830 a, 830 b. To do so, the secondsub-portion 826 b may distally extend past the first sub-portion 826 aso that the second sub-portion 826 b is electrically connected to themetal cannula 830 b, and a gap 862 electrically isolates the secondsub-portion 826 b from the metal cannula 830 a. Similarly, the firstsub-portion 826 a may proximally extend past the second sub-portion 826b so that the first sub-portion 826 a is electrically connected to themetal cannula 830 a, and a gap 864 electrically isolates the firstsub-portion 826 a from the metal cannula 830 b. In other exampleembodiments, one or both of the metal cannulas 830 a, 830 b may bereplaced with an opening in the tubular member 102 (such as the opening150 shown in FIG. 1A). The conductive ink making up the firstsub-portion 826 a may extend into one of the openings to be electricallycoupled with the first return wire 832 a. Similarly, the conductive inkmaking up the second sub-portion 826 b may extend into the other openingto be electrically coupled with the second return wire 832 b.

The return wires 832 a, 832 b may be disposed within the tubular memberin various combinations of the embodiments shown in cross-section inFIGS. 4-6. For example, one of the return wires 832 a, 834 b may bedisposed within one of the lumens, such as the injection lumen, so thatone of the lumens serves a dual purpose as described above. The other ofthe return wires 832 a, 832 b may be embedded as an integral componentof the tubular member 102. Alternatively, one of the return wires 832 amay be disposed within a lumen serving a dual purpose and the otherreturn wire 832 b may be disposed within a lumen having a sole purposeto house the return wire 832 b. Alternatively, both of the return wires832 a, 832 b may be embedded within the tubular member 102, or each ofthe return wires 832 a, 832 b may be disposed in respective lumens, eachof which has a sole purpose of housing the return wire 832 a or 832 b.Various configurations are possible. In the tubular member 102, thereturn wires 832 a, 832 may longitudinally extend parallel orsubstantially parallel to each other.

In one example configuration, as shown in FIG. 8, the gap 860 separatingand electrically isolating the first and second sub-portions 826 a, 826b may longitudinally extend along the outer surface of the distalportion in a straight or substantially straight direction. Inalternative configurations, the gap may longitudinally extend in anon-straight manner. For example, as shown in FIG. 9, a gap 960 may havea zig-zag pattern. As another example, referring to FIG. 10, the gap1060 may have a sinusoidal pattern. Various other patterns may be usedfor the gap, such as helical or spiral, as examples. Alternatively, thegap may not necessarily have a pattern, but may extend in a generallynon-straight manner along the outer surface of the distal portion 106.Configuring the gap to extend in a non-straight manner or have anon-straight pattern may be advantageous over configurations where thegap extends straightly in that the non-straight configurations mayfacilitate contact for both the first and second sub-portions of theconductive ink with the sphincter muscle or surrounding tissue.

Referring back to FIG. 1, the return cabling 144 may be configured toconnect to various types or configurations of the power source 118and/or of the return port 146 of the power source 118. In manysituations, the power source 118 used to connect to the bipolarsphincterotome 100, may have been configured, such as when manufactured,to connect to and/or receive return cabling for monopolarsphincterotomes, which may use a solid neutral electrode or a splitneutral electrode as part of the return path. Some power sources 118 maybe configured to receive and/or connect to a single return path (e.g., amonopolar sphincterotome that uses a solid neutral electrode), tworeturn paths (e.g., a monopolar sphincterotome that uses a split neutralelectrode), or both.

For the bipolar sphincterotome configurations, the return cabling 144electrically coupling the return path 124 to the return port 146 of thepower source 118 may be configured in various ways to accommodate boththe single and dual path configurations of the bipolar sphincterotome100 as well as a power source 118 configured to recognize a solidneutral electrode, a split neutral electrode, or both.

Referring to FIG. 11, where the bipolar sphincterotome 100 includes asingle return path, to connect to a power source 118 that is configuredto recognize a solid neutral electrode, the return cabling 144 mayinclude a single wire 1102 that is connected to a single return wire132. The wire 1102 may proximally terminate at a plug 1104 that isadaptable to connect and electrically couple the wire 1102 to the returnport 146 of the power source 118.

Referring to FIG. 12, where the bipolar sphincterotome 100 includes tworeturn paths, to connect to a power source 118 that is configured torecognize a split neutral electrode, the return cabling 144 may includetwo wires 1202, 1203 electrically isolated from each other. One of thewires 1202 in the return cabling 144 may be connected to one of thereturn wires 1232 a, and the other wire 1203 in the return cabling 144may be connected to the other return wire 1232 b. Each of wires 1002,1003 may proximally terminate at a plug 1204 that is adaptable toconnect and electrically couple the wires 1202, 1203 to the return port146.

For some power sources 118, the return port 146 may be configured toconnect to two return paths, even though the power source 118 may beconfigured to recognize a solid neutral electrode. For theseconfigurations, the return cabling 144 may include two wires that areconfigured so that the power source 118 recognizes a solid neutralelectrode. Referring to FIG. 13, where the bipolar sphincterotome 100includes a single return path, to connect to a power source 118 that isphysically configured to receive two return paths but is also configuredto recognize a solid neutral electrode, the return cabling 144 mayinclude two wires 1302, 1303 that are shorted together at a distal endof the wires 1302, 1303, where they also may be connected to a proximalend of the single return wire 132. Each of wires 1302, 1303 mayproximally terminate at a plug 1304 that is adaptable to connect andelectrically couple the wires 1302, 1303 to the return port 146. Forthis configuration, the power source 118 may determine or recognize anominal resistance between the two return paths, just as it would for asolid neutral electrode.

Where the return port 146 is configured to connect to two return paths,and the power source 118 is configured to recognize a split neutralelectrode, a resistance may be included in one of the wires in thereturn cabling 144 where the return path 124 of the bipolarsphincterotome includes a single return path. Referring to FIG. 14, aresistive element or resistor 1410 may be added to or included in one ofwires 1402, 1403 of the return cabling 144 so that a resistance existsbetween the two wires 1402, 1403. The wires 1402, 1403 may then beconnected together at their distal ends, where they may be connected tothe single return wire 132. The resistance chosen for the resistiveelement 1410 may be in range that the power source 118 may be configuredto measure or recognize the bipolar sphincterotome 100 as using a splitneutral electrode. In some examples, the range may be about 5-150 Ohms,although other resistances may be used depending on the power source118. The value of the resistance may be optimized to work for multipleor various types of power sources 118.

Alternatively, the resistance for the resistive element 1410 may be avalue that may cause the power source 118 to recognize the bipolarsphincterotome 100 as using either a solid neutral electrode or a splitneutral electrode. Some power sources 118 are configured to use an upperlimit for resistance that the power source 118 may accept to recognize asolid neutral electrode, while also having a lower limit for resistancethat the power source 118 may accept to recognize a split neutralelectrode. For these power sources 118, if there is an overlap betweenthe upper and lower limits, the resistance for the resistive element1410 may be chosen in the overlap, and no errors may be identified bythe power source 118 whether the power source 118 is set to recognizeeither a solid neutral electrode or a split neutral electrode.

In an alternative embodiment, resistive elements may be included in bothof the wires in the cabling. Referring to FIG. 15, a resistive element1510 may be included in a wire 1502, and a resistive element 1512 may beincluded in a wire 1503 of the return cabling 144. The sum of theresistances of the resistive elements 1510, 1512 may be equal to aresistance of a single resistive element where only one of the wiresincludes a resistive element (e.g., resistive element 1410 shown in FIG.14). Additionally, the resistances of the resistive elements 1510, 1512may be the same or substantially the same. Resistive elements 1510, 1520may be included in both of the wires 1502, 1503 in order to split thepower between the two wires 1502, 1503. Heat generated by the tworesistive elements 1510, 1512 may be reduced, compared to the singleresistive element configuration shown in FIG. 14, because less power maybe drawn through each of the resistive elements 1510, 1512. Using tworesistive elements 1510, 1512 may also minimize or eliminate polarity inthe return path, which may pose safety or performance problems for thesphincterotome.

The foregoing description of various embodiments of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the preciseembodiments disclosed. Numerous modifications or variations are possiblein light of the above teachings. The embodiments discussed were chosenand described to provide the best illustration of the principles of theinvention and its practical application to thereby enable one ofordinary skill in the art to utilize the invention in variousembodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the invention as determined by the appended claimswhen interpreted in accordance with the breadth to which they arefairly, legally, and equitably entitled.

1. A bipolar sphincterotome to perform a sphincterotomy at a treatmentsite within a patient, the bipolar sphincterotome comprising: anelongate tubular member; a cutting wire disposed within the tubularmember, except for a cutting edge of the cutting wire, where the cuttingedge protrudes from the tubular member; a first return path; and asecond return path substantially electrically isolated from the firstreturn path, wherein the first return path comprises a first returnwire, the second return path comprises a second return wire, the firstand second return wires longitudinally extending within the tubularmember from a distal portion to a proximal portion of the tubularmember.
 2. The bipolar sphincterotome of claim 1, wherein the firstreturn path further comprises a first conductive ink portionelectrically coupled to the first return wire, and wherein the secondreturn path further comprises a second conductive ink portionelectrically coupled to the second return wire.
 3. The bipolarsphincterotome of claim 2, further comprising: a first conductivecannula disposed about the outer surface of the tubular member, thefirst conductive cannula electrically coupling the first conductive inkportion to the first return wire; and a second conductive cannuladisposed about the outer surface of the tubular member, the secondconductive cannula electrically coupling the second conductive inkportion to the second return wire, wherein the first conductive cannulaand the second conductive cannula are disposed at opposing ends of thefirst and second conductive ink portions.
 4. The bipolar sphincterotomeof claim 2, further comprising: a first skive in the tubular memberextending from the outer surface to a location within the tubular memberthat is in communication with a distal end of the first return wire,wherein the first conductive ink portion extends within the first skiveto be electrically coupled with the first return wire; a second skive inthe tubular member extending from the outer surface to a location withinthe tubular member that is in communication with a distal end of thesecond return wire, wherein the second conductive ink portion extendswithin the second skive to be electrically coupled with the secondreturn wire, wherein the first skive and the second skive are disposedat opposing ends of the first and second conductive ink portions.
 5. Thebipolar sphincterotome of claim 2, wherein a gap separating the firstconductive ink portion from the second conductive ink portionsubstantially electrically isolates the first conductive ink portionfrom the second conductive ink portion.
 6. The bipolar sphincterotome ofclaim 5, wherein the gap longitudinally extends in a substantiallystraight pattern.
 7. The bipolar sphincterotome of claim 5, wherein thegap longitudinally extends in a non-straight pattern.
 8. The bipolarsphincterotome of claim 5, wherein the gap longitudinally extends in azig-zag pattern.
 9. The bipolar sphincterotome of claim 5, wherein thegap longitudinally extends in a sinusoidal pattern.
 10. The bipolarsphincterotome of claim 1, wherein the first return wire longitudinallyextends within a first lumen of the tubular member, and wherein thesecond return wire longitudinally extends within a second lumen of thetubular member.
 11. The bipolar sphincterotome of claim 10, wherein atleast one of the first lumen or the second lumen has two or morefunctions, one of the two or more functions being to house the firstreturn wire or the second return wire.
 12. The bipolar sphincterotome ofclaim 1, wherein the first return wire longitudinally extends with afirst lumen of the tubular member, and wherein the second return wire islongitudinally embedded as an integral part of the tubular member. 13.The bipolar sphincterotome of claim 1, wherein the first return wire andthe second return wire are each embedded as an integral part of thetubular member.